Maybe just stuff like that is enough to make a difference.
I grew up speaking multiple languages. My monolingual friend once asked in which language I dream, and I said - "not sure, I think in all three different ones I'm currently fluent". "But how do you know?", he kept pressing. "Ah, well, they come with subtitles", I joked. But since then I often wonder, how do we recognize a language in our dreams?
I am mostly monolingual but I would expect them to come with a language tag too. I believe a dream about Bob talking about cats in Spanish would directly activate your neural network like V_cats + V_spanish + V_bob_is_talking without activating the parts that would decode auditory input into that semantic vector.
Yes. This is exactly what you should be asking with this kind of stuff. The research is hopelessly confounded by social status traits that correlate with wealth.
And before anyone says it, the abstract claiming "adjustment for linguistic, physical, and sociopolitical exposome factors" is fine, but it's essentially impossible to control for something as pervasive as the effects of wealth, without randomization. There are also factors -- like the culture you grew up in -- that are equally difficult to control. For example, if your dataset has only X multi-lingual Americans, and 1000x multi-lingual Western Europeans, no amount of statistical massage will correct for the imbalance.
And, just thinking about other cultures
I also find myself exercising verbal skills possibly unnecessarily (with a language learning app that's certainly not immersion) but probably predictably.
I've heard that they say to exercise mental arithmetic skills if stranded on a desert island with no reading material; and that it's normal to develop self dialogue in solitary
Some of these immigrants are very well supported with a strong social network, while others struggle with isolation.
In fact it's two separate questions because it can go both ways, heavily.
Interesting food for thought, thanks for posting.